/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.cf.attrib;

import com.android.dx.rop.cst.CstDouble;
import com.android.dx.rop.cst.CstFloat;
import com.android.dx.rop.cst.CstInteger;
import com.android.dx.rop.cst.CstLong;
import com.android.dx.rop.cst.CstString;
import com.android.dx.rop.cst.TypedConstant;

/**
 * Attribute class for standard {@code ConstantValue} attributes.
 */
public final class AttConstantValue extends BaseAttribute {

	/** {@code non-null;} attribute name for attributes of this type */
	public static final String ATTRIBUTE_NAME = "ConstantValue";

	/** {@code non-null;} the constant value */
	private final TypedConstant constantValue;

	/**
	 * Constructs an instance.
	 * 
	 * @param constantValue
	 *            {@code non-null;} the constant value, which must be an
	 *            instance of one of: {@code CstString}, {@code CstInteger},
	 *            {@code CstLong}, {@code CstFloat}, or {@code CstDouble}
	 */
	public AttConstantValue(TypedConstant constantValue) {
		super(ATTRIBUTE_NAME);

		if (!((constantValue instanceof CstString)
				|| (constantValue instanceof CstInteger)
				|| (constantValue instanceof CstLong)
				|| (constantValue instanceof CstFloat) || (constantValue instanceof CstDouble))) {
			if (constantValue == null) {
				throw new NullPointerException("constantValue == null");
			}
			throw new IllegalArgumentException("bad type for constantValue");
		}

		this.constantValue = constantValue;
	}

	/** {@inheritDoc} */
	public int byteLength() {
		return 8;
	}

	/**
	 * Gets the constant value of this instance. The returned value is an
	 * instance of one of: {@code CstString}, {@code CstInteger},
	 * {@code CstLong}, {@code CstFloat}, or {@code CstDouble}.
	 * 
	 * @return {@code non-null;} the constant value
	 */
	public TypedConstant getConstantValue() {
		return constantValue;
	}
}
